The benefit of fixed squad rosters in those games is because matches are quite small. With the size and scale of PS, it actually pays to be experienced with all the different people in the outfit, and be more adaptable. Its not like you can play throwaway matches between the scheduled fixed squad matches, every fight you take part in is a live fight, contributing to the same war.

I say steer clear of fixed squad rosters, as it creates and reinforces cliques and elitism.